A psychiatrist once told me to avoid eating bone marrow because it could contain prions that could cause dementia. However, I haven't been able to find any studies that confirm this. Could this happen?
You might be referring to Creutzfeldt-Jakob disease (CJD). It is transmitted through exposure to brain tissue and spinal cord fluid from infected individuals.
CJD is characterized by rapidly progressive dementia.
The leading scientific theory at this time maintains that CJD and the other transmissible spongiform encephalopathies (TSEs) are caused by a type of protein called a prion.
CJD is indeed caused by prions: proteins that occur in both a normal form, which is a harmless protein found in the body’s cells, and in an infectious form, which causes disease. The harmless and infectious forms of the prion protein have the same sequence of amino acids, but the infectious form of the protein takes a different folded shape than the normal protein. Sporadic CJD may develop because some of a person’s normal prions spontaneously change into the infectious form of the protein and then alter the prions in other cells in a chain reaction.
Prions are sort of protein with such a distorted conformation that convert its benign/ essential form into prion forms. Thus they can multiply which is comparable to reproduction in virus and viroids.
if an animal is infected with prions then it is better to not eat any of the part of that animal. Not necessarily bone marrow but of any part. Prion disease also spreads through funerary cannibalism ritual. . Prion is a great concern about biosafety. Prion-infected cattles are not burried or left into nature but incinerated. There are disputes about whether burning is sufficient. Dementia is too mild term to describe prion infection, they are extreme debilitating, progressive, usually fatal, and usually affect the brain and nervous system. Most prion diseases are fatal within a few months, though some can last a few years.
Prions can also spread through grafting, blood transfusion etc. and standard biosafety procedures to kill bacteria and virus does not work on prions. They require a more harsh sterilisation procedure.